At What Point Is Something No Longer Itself?

[WWLabRat]

This was brought on by a discussion between a friend of mine and I a while back. Simply put, the question is the same as the title: At what point does something stop being what it was before. Example: You have a wooden boat with long wooden planks from one end to the other with all the accouterments needed to hold it all in place. As time goes on, parts of the boat are replaced as they wear out, warp, etc. Eventually every board, every screw, bolt, and nut has been replaced with a new one. Is it still the same boat? If yes, how can it still be the same if nothing on it is the same as it was before being fixed? If no, how does that apply to living beings? Our cells are constantly multiplying, dividing, and dying off, yet you are still you... The cells you have now aren't the same ones that were there at your birth. So are you the same person that you were back then?

 

This same question is put forth when examining the beaming capabilities of the Star Trek universe. In the time presented during the show, civilization has developed the ability to "beam" matter to different locations. With our known understanding of how the universe works, we would have to break things down at the molecular level and reconstruct it at the target location, making sure each atom is exactly where it was supposed to be at the origin. Doesn't seem so bad at first when transporting non living matter. But as with the above example with cells, would the person at the target location still be you? You would be broken down, atom for atom, essentially killing you off every time, just to be put back together on the other end. Would you still be the same person? And what would this mean when it comes to individuality and identity?

[Z07]

http://en.wikipedia.org/wiki/Ship_of_Theseus

 

Perception is determined by perspective.

 

Originality can mean different things to different people in various circumstances.

 

The late Boyd Coddington committed a type of fraud in this area by registering newly crafted cars using the VINs from rusted junk to avoid taxes and modern safety and emissions regulations. So from the perspective of the state of California the cars were not originals.

 

Conversely, in the age of sail, insurers were all too happy to allow a completely overhauled ship to take the place of an aged one on an agreed value contract. The risk went down for them and the owner so both parties benefitted.

[Tridimity]

It's an interesting question, WWLabRat. At what point does river X stop being river X? Water molecules are constantly flowing and so the description of the river at time point A, in terms of the precise arrangement of water molecules and other matter comprising the river, will be considerably different to the arrangement of molecules at time point B - even between time points separated by mere fractions of a second. By convention, the body of water would continue to be referred to as 'river X' until a noticeably drastic change occurred (e.g. drying up completely). Probably the limits of identification are determined to some extent by matters of scale: a few water molecules, here and there, relative to the size of the body of water and to the size of the observing human, is not such a big deal. Perhaps if we were to observe things from the perspective of a bacterium, each individual water molecule would suddenly have more importance in determining the identity of the body of water? As for human identity - our cells die and are replaced throughout life but our individual genome sequence passes, consistently (except for mutations and epigenetic effects) down the cell generations. As such, the genome sequence confers a unique identity upon each individual.

Also, perhaps the time frame of observation is an important contributing factor when defining identity. Perhaps we should define people and objects according to their entire lifespan or existence, rather than as a static object at one point in time. The former is counter-intuitive because, in general, in life, we need to be able to identify people and objects on the basis of how we find them at a particular time point - and so we have become accustomed to so doing. However, the question is, where to draw the line? Is a person defined at the baby up to the deceased? Should the foetus be involved in the identification of the person? Should the gametes? By extension, should the parents and offspring; the ancestors way back to the universal ancestor? Should all of the descendants be included? Nothing exists in isolation, and so, in a sense, we all share identity.